Basically, most feed pellet producing systems include a bin for containing a source of material from which the pellets are to be made, a mixer/conditioner where selected amounts of heat and moisture are added to the material as it is fed from the bin, and a pellet producing means such as a die into which the material is fed from the mixer/conditioner. Suitable means, such as augers, chutes, and the like, are provided to move the material from the bin, through the conditioner, and into the producing means at selected rates. Also included in most such systems are sources of heat and moisture and means for selectively supplying them to the mixer/conditioner for proper mixing with the material.
The pellet producing means is operated by an electric motor which presently, for example, may be from 25 to 300 horsepower. By way of example, a die-type pellet producing means consists of a large hollow cylinder with a large number of radial holes through its wall, and a plurality of rollers mounted within the cylinder in contact with its inside wall. As the cylinder rotates, by means of the electric motor, thereby imparting rotation to the rollers, and as the material is fed into the cylinder, the interaction of the rotating cylinder with the rotating rollers compresses and forces the material through the holes to form solid, worm-like masses which are severed as they are formed to produce pellets.
The load on the producing means, and hence the productivity and efficiency of the system, is dependent on several factors as is the quality of pellets produced.
First, load is, of course, dependent in a direct relationship on the rate at which milled material is fed to the producing means; the faster the feed rate, the greater the load.
Second, load is dependent on the composition of the milled material and its temperature and moisture content as it is fed into the producing means. These factors also have a great effect on pellet quality. It has also been found that for a given animal feed formulation there is a temperature and moisture content of the material at the pellet producing means for optimum pelleting.
These are numerous ingredients commonly used to compose animal feed materials for use in pelleting. The following are given by way of example as being among them:
1. (Water Insoluble) PA1 2. (Water Soluble) PA1 3.
Wheat Bran PA2 Wheat Midds PA2 Gluten Feed PA2 Brewer's Grain PA2 Distiller's Grain PA2 Hominy Fibers: Soybean Hulls, Cottonseed Hulls, Alfalfa, Malt Hulls, Etc. PA2 Urea PA2 Milk PA2 Sugar PA2 minerals PA2 Corn PA2 Milo Maize
These are given as examples. Many other ingredients could be included so that the possible animal feed formulations are numerous. But, for each such formulation, there is a temperature and moisture content of the material at the pellet producing means for optimum production and quality. A more complete discussion on the control of temperature and moisture to improve the quality and quantity of pellet production is contained in U.S. Pat. No. 3,573,924.
Hence, it has heretofore been recognized that temperature and moisture content are critical for the high quality and quantity production of pellets including proper loading of the producing means. With prior art systems the parameters such as feed rate and temperature and moisture content of the material have been controlled manually, or at best with the aid of an automatic control on one or more of the parameters independently. The result has been inefficient and often poor quality pellet production caused by the ineptness of the operator, his inability to act quickly enough as the conditions in the system change, or his unwillingness to continually monitor the system. Often overloads occur on the producing means requiring a shutdown of the motor and causing a severe clogging of the producing means that may take hours to remove. Such shutdowns are costly and aggravating, and to avoid them it is common practice to operate the system at a greatly reduced capacity.
While the solutions of these problems have not heretofore been found, the automatic system of this invention overcomes these problems to provide a system that greatly increases the quality and production of pellets, and increases the life of the producing means by providing optimum operating efficiency.